JPS59155720A - Liquid level detecting apparatus - Google Patents

Abstract

PURPOSE:To simplify the structure of the titled apparatus by dispensing with the provision of the wiring of an electric signal in the vicinity of a tank and to make it possible to easily detect the position of the boundary surface between liquids having different specific gravities, by detecting the position of the boundary surface between liquids having different specific gravities by detecting the position where a light blocking plate blocks the optical signal from a light emitting part. CONSTITUTION:A large number of slits 8a are provided to the light blocking plate 8 supported by the support rod 7a of a float 7 while optical fibers 6, 9 are arranged at constant positions opposed so as to interpose the light blocking plate 8 therebetween. The light emitted from the emitting surface of the optical fiber 6 is formed into a fine beam passing one slit 8a and passes the slit 8a at a predetermined position to reach the light receiving surface of the optical fiber 9. If the optical signal received by the optical fiber 9 is digitally counted by a light receiving apparatus 10, the position of the slits 8a of the slit plate 8 moved in cooperated relation to the movement of the float 7, that is, the boundary surface L1 between liquids having different specific gravities can be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid level detection device for detecting the position of an interface between liquids having different specific gravities in a tank storing a plurality of liquids having different specific gravities.

Conventionally, liquid level detection devices for liquids stored in containers, etc., have generally used a method such as a float floating on the top surface of the liquid (at the boundary between gas and liquid), and since all of these are mechanically operated, the structure is It has the disadvantage that it is complicated and the device is large, and there is also a disadvantage that there is a risk of fire due to electrical sparks when using flammable liquids such as oil or explosive liquids because electrical wiring is provided. Furthermore, conventional devices of this type have been able to simply detect the liquid level, but have not been able to detect the interface between liquids with different specific gravities.

However, in tankers and the like, seawater is often collected under the oil in order to stabilize the ship, and it is necessary to know the position of the water surface under the oil in order to know the amount of oil remaining. Also,
It is necessary to know the boundary between oil and water, which have different specific gravities, even if there are various types of liquids with different specific gravities, for example, in an oil tank where water is naturally stored.

In order to meet this demand, the present applicant previously developed a liquid level detection device as shown in Fig. 1 and filed an application (Japanese Patent Application No.
No. 182783). In the figure, 1 is a tank for storing a plurality of liquids having different specific gravities, and in the figure, a layer of water 3 is formed under 20 layers of oil. Reference numeral 4 denotes a main body of the liquid level detection device, which has a cylindrical structure with a closed top surface, and a bottom surface that is in close contact with the bottom surface of the tanker 1. Liquid level detection device body 4
is further divided into a liquid flow section 4a and a liquid level detection section 4b. A plurality of liquid outlet holes 4C are provided in the liquid outlet part 4a. In addition, the tank 1 outside the liquid level detection device main body 4
A boundary surface L2 is formed at the same position as the boundary surface between the oil 2 layer and the water 3 layer inside, and which moves in conjunction with the boundary surface L2. Also,
The liquid detection section includes a light emitting section 4d which is divided into a plurality of equally spaced light emitting surfaces a-g, and a light receiving surface a' to g which is also divided into a plurality of equally spaced sections facing the light emitting section 4d. A light-receiving section 4e is provided. Reference numeral 5 denotes a light emitting device consisting of a light emitting element. An optical signal from the light emitting device 5 is transmitted through an optical fiber cable 6 for transmitting the light emitting signal, and the light emitting surfaces a-g of the light emitting section 4d are also received by the light receiving section 4e. Surface a'
An optical signal is emitted towards ~g'.

A float 7 is installed at the interface between the oil 20 layer and the water 3 layer, and has a specific gravity equal to or thicker than that of the oil 2 (and smaller than the specific gravity of the water 3).

Reference numeral 8 denotes a light shielding plate which blocks light emitted from the light emitting part 4d, is connected to the float 7 by a support rod 1a, and moves up and down in conjunction with the up and down movement of part 7).

Reference numeral 9 denotes an optical fiber cable for transmitting a received light signal, which transmits the optical signal received by the light receiving section 4e. 10 is a light receiving device that converts an optical signal into an electrical signal.

Reference numeral 11 denotes a display device such as a display or indicator for displaying the output electrical signal of the light receiving device 11.

Next, the operation of the liquid level detection device will be explained.

The optical signal from the light emitting device 5 is transmitted through the optical fiber cable 6 to the light emitting surfaces a-g, which are divided at regular intervals, of the light emitting section 4d of the liquid level detection device main body 4, and then to the light receiving surfaces a' to a of the light receiving section 4e.
The optical signal emitted from this light emitting surface 9%g is received by the corresponding front light receiving surfaces a' to g', and passes through the optical fiber cable 9 to the light receiving device 111.
The signal reaches t10, is converted into an electrical signal by the light receiving device 10, and is displayed on the display device 11. Here, the light shielding plate 8 supported by the support rod 7a of the float 7 blocks a part of the optical signal emitted from the light emitting surfaces a-g of the light emitting part 4d.
The optical signal in that portion will not reach the light receiving surfaces a' to 〆 of the light receiving section 4e. By detecting the positions of the light-receiving surfaces a' to g' of the light-receiving portion 4e that do not receive light, it is possible to know the interface between liquids having different specific gravities. In addition, as mentioned above, the interface between liquids with different specific gravities in the tank 1,
When the float 7 and the light shielding plate 8
It's also on the boundary.

Both will be displaced, and the display device 11 will display the boundary surface L1 of the tank 1. Liquid level detection device body 4
As mentioned above, since it has a cylindrical structure with the upper surface closed, the liquid discharge hole 4C is provided with the liquid discharge hole 4C.
The liquid in tank 1 comes out, but the liquid comes out from hole 4C.
No liquid flows into the liquid level detecting section 4b where is not provided.

In the liquid level detection device previously filed by the applicant, the light emitting surface a%g of the light emitting section 4d and the light receiving surfaces a' to g of the light receiving section 4e are
' are arranged opposite each other with the light shielding plate 8 in between, so if the detection accuracy of the liquid level is increased or the detection height is increased, the number of optical fibers composing the optical fiber cable 6.9 will be increased. The disadvantage is that there are too many. Also,
There is also a drawback that the inner surface of the liquid level detecting part 4b is contaminated due to evaporation of the liquid because the liquid enters the liquid outlet part 4a of the liquid level detecting device main body 4.

This invention was made in view of the above points, and instead of the light shielding plate of the liquid level detection device previously filed by the applicant, a light shielding plate provided with a large number of slits is used, and this light shielding plate is sandwiched between the light shielding plates. A light emitting part that emits a thin beam of light and a light receiving part that receives this light are provided at opposing positions, and the slit position through which the light emitted from this light emitting part passes is detected to detect the boundary between different liquids. Detect the surface or mark the boundary surface position +i on the light shielding plate, and set the scale on the light shielding plate that is not illuminated by the thin beam-shaped light emitted from the light emitting part! It is an object of the present invention to provide a liquid level detection device that detects a boundary surface by reading the alpha angle. The present invention will be explained below based on the drawings.

FIGS. 2(a) and 2(b) are perspective views showing the shape of a light shielding plate of a liquid level detection device according to an embodiment of the present invention.

In FIG. 2(a), a light shielding plate 8 supported by a support rod 7a of a float 7 is provided with a large number of shields 8a. An optical fiber is placed at a fixed position opposite to the light shielding plate 8.
R bar cables 6 and 9 are arranged. The light emitted from the emitting surface of the optical fiber cable 60 is formed into a thin beam that passes through one slit 8a, and the light emitted from the emitting surface of the optical fiber cable 6 is formed into a thin beam that passes through one slit 8a.
It passes through 8a and reaches the light receiving surface of the optical fiber cable 9.

The optical signal received by the optical fiber cable 9 is transferred to the optical receiver 1.
By digitally counting at 0, it is possible to detect the position of the light shielding plate 8 (8a) that moves in conjunction with the movement of the float 7, that is, the boundary between liquids with different specific gravity.

FIG. 2(b) shows a modification of FIG. 2(a), in which a rack 22 is supported on the support rod 7a of the float 7.
A pinion 23 is provided so as to mesh with the pinion 23. The pinion 23 is provided with a disc-shaped light-shielding plate 21 having a large number of shields 21a arranged around its circumference. This light shielding plate 2
The optical fiber cables 6 and 9 are arranged at fixed positions facing each other with the optical fiber 1 in between, as in the case of FIG. 2<8).

The rack 22 moves up and down in accordance with the up and down movement of the float 7, and the up and down movement of the rack 22 causes the pinion 23 and the light shielding plate 21 to rotate clockwise or counterclockwise. By counting digitally from the emitting surface of the optical fiber cable 6, the position of 21a of the light shielding plate 21 that moves in conjunction with the movement of the float 7, that is, the boundary between liquids with different specific gravity can be detected. .

FIG. 3 is a perspective view showing another embodiment of the light shielding plate of the present invention. In the figure, reference numeral 24 denotes a transparent or semi-transparent light-shielding plate having a scale 24a. A thin beam of light is emitted from the emission surface of the optical fiber cable 250 from behind the light shielding plate 24, and this light is focused onto the optical fiber cable 27 by the condenser lens 2B, which is attached to the other end of the optical fiber cable 26. By directly reading the characters on the light shielding plate 24 with the magnifying lens 2B, the boundary surface L1 between liquids having different specific gravities is detected.

FIGS. 4(a) and 4(b) are views showing a modified example of the float portion of a liquid level detection device which is an embodiment of the present invention; FIG. 4(a) is a sectional view, and FIG. FIG. Reference numeral 31 denotes a main body of the detection device, and the main body 31 of the detection device has a closed cylindrical shape, and has a structure in which liquid does not enter into the main body 31 of the detection device. 32 is a float, and this float 32 has a donut shape that fits around the outer periphery of the detection device main body 31, and its specific gravity is selected so that it is located at the interface between liquids having different specific gravity. 33 is a magnet provided on the inner peripheral surface of the float 32 formed in the shape of a donut. 34 is a light shielding plate stand, and the detection device main body 31
It has a disc shape that fits inside the. A magnet 35 is provided on the outer periphery of the light shielding plate base 34, and has a polarity that attracts the magnet 33 to each other.

The float 32 also moves up and down as the boundary surface between the liquids having different specific gravity changes up and down. When the float 32 moves up and down, the attraction force between the magnets 33 and 35 causes the light shielding plate base 34 to
It also moves up and down. As the light-shielding plate stand 34 moves up and down, the light-shielding plate 8 supported by the support rod 34a provided on the light-shielding plate stand 34 also moves up and down. By digitally counting the light that reaches the light receiving surface of the cable 9, the position of the boundary surface L1 between liquids having different specific gravities can be detected.

By adopting the structure as shown in FIG. 4 above, liquid will not infiltrate into the detection device main body unlike the liquid level detection device shown in FIG. The inner surface is not contaminated (liquid level can be detected stably over a long period of time).

As explained above, the liquid level detection device according to the present invention is
In a device for detecting the position of an interface between liquids with different specific gravities in a tank storing a plurality of liquids with different specific gravities, the specific gravity is selected so as to be located at the interface between the liquids with different specific gravities. a float that operates in conjunction with the float, a light shielding plate that operates in conjunction with the float, a light emitting unit that emits a thin beam-shaped optical signal installed at a position facing the light shielding plate, and a light receiving unit that receives this optical signal. The structure is extremely simple because the light shielding plate detects the position where the light (i) from the light emitting part is shielded and detects the position of the interface between the liquids having different specific gravities. This makes it easy to detect the position of the interface between liquids with different specific gravity, and there is no need to install electrical signal wiring near the tank, making it suitable for liquid level detection in tanks storing flammable and explosive liquids. Demonstrates extremely excellent effects.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a schematic configuration of a liquid level detection device previously filed by the present applicant, and Fig. 2 (a) and (+)) are shading diagrams of a liquid level detection device H which constitutes an embodiment of the present invention. FIG. 3 is a perspective view showing an embodiment of the light-shielding plate of the present invention, and FIG. FIG. 3 is a cross-sectional view and a perspective view of a float portion. In the figure, 1 is a tank, 2 is oil, 3 is water, 4 is the liquid level detection device body, 5 is a light emitting device, 6 is an optical fiber cane, 1 is a float, 8 is a light shielding plate, 9 is an optical fiber cable, 10 is a light receiving device, 11 is a display device, 21 is a light shielding plate, 22 is a rank, 23 is a pinion, 24 is a one-degree light plate, 25 is an optical fiber cable, 26 is a condensing lens, 27 is an optical fiber knob, and 28 is a magnifying lens , 31 is a main body of the detection device, 32 is a float, 33 is a magnet, 34 is a light-shielding plate stand, and 35 is a magnet. Figure 1 Figure 2 (a) (b) Figure 4 (a) Strategy 3

Claims (4)

[Claims] (1) In a device for detecting the position of an interface between liquids with different specific gravities in a tank storing a plurality of liquids with different specific gravities, A light emitting part that emits a beam-shaped light signal with a light shielding plate located opposite to the float with a specific gravity selected as 7--, a light shielding plate that operates in conjunction with this float, and a light beam shaped like a light signal located at a position opposite to each other with this light shielding plate in between. and a light receiving part that receives the optical signal, and detects the position of the interface between the liquids having different specific gravities by detecting the position where the light shielding plate blocks the optical signal from the light emitting part. A liquid level detection device featuring: (2) The scope of claims characterized in that the light shielding plate is provided with a large number of slits, and the position where the light shielding plate blocks the optical signal is detected from the slit position through which the optical signal emitted from the light emitting section passes. The liquid level detection device according to item (1). (3) The light shielding plate is provided with a large number of scales, and the position where the light shielding plate blocks the optical signal emitted from the light emitting section is directly read. Liquid level detection device. (4) Claim (1) characterized in that the interlocking operation of the float and the light shielding plate is configured such that a magnet is used to indirectly transmit the operating force of the float to the light shielding plate using magnetic force. The liquid level detection device described.